Principal.cs

using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;

namespace R815ImprimirVariosDocumentos
{
    public partial class Principal : Form
    {
        public Principal()
        {
            InitializeComponent();
        }

        private void btnImprimir_Click(object sender, EventArgs e)
        {
            string[] textoImpresion = new string[101];
            for (int i = 0; i < 101; i++)
            {
                textoImpresion[i] = i.ToString();
                textoImpresion[i] += ": Programad como un profesional.";
            }

            PrintDocument documento = new DocumentoTexto(textoImpresion);
            documento.PrintPage += documento_PrintPage;

            PrintDialog printDialog = new PrintDialog();
            printDialog.Document = documento;

            if (printDialog.ShowDialog() == DialogResult.OK)
            {
                documento.Print();
            }
        }

        private void documento_PrintPage(object sender, PrintPageEventArgs e)
        {
            DocumentoTexto doc = (DocumentoTexto) sender;

            using (Font fuente = new Font("Trebuchet", 10))
            {
                float altoLinea = fuente.GetHeight(e.Graphics);

                float x = e.MarginBounds.Left;
                float y = e.MarginBounds.Top;

                doc.NumeroPagina += 1;

                while ((y + altoLinea) < e.MarginBounds.Bottom && doc.Desplazamiento <= doc.Texto.GetUpperBound(0))
                {
                    e.Graphics.DrawString(doc.Texto[doc.Desplazamiento], fuente, Brushes.Black, x, y);

                    doc.Desplazamiento += 1;

                    y += altoLinea;
                }

                if (doc.Desplazamiento < doc.Texto.GetUpperBound(0))
                {
                    e.HasMorePages = true;
                }
                else
                {
                    doc.Desplazamiento = 0;
                }
            }
        }
    }
}